The present invention relates to a tablet arm for furniture, particularly a chair. More specifically, the invention concerns a work tablet that mounts to a chair and uses an assembly having two or more degrees of freedom to pivot and rotate the tablet from a vertical stowed position at the side of the chair to an deployed position above and parallel to the seat of the chair.
A number of chair tablet designs have a mechanism that support the work tablet in a first horizontal position over the chair seat and in a second stowed position when the tablet is not in use. However, few designs have provided an apparatus that can be integrated into the chair design and that allow repositioning of the tablet from above the chair seat to a position to the side of the chair by both rotating the tablet from the horizontal plane to the vertical plane or, when the tablet is in use, by merely swinging the tablet in the horizontal plane. Further, as an easily mountable accessory to a chair, none of the existing tablet designs provide rotation of the tablet from the horizontal plane to the vertical plane and independent rotation in the vertical plane to a stowed position along the side of the chair using a single inexpensive two-axis hub.
One design that provides a horizontal tablet position above a chair and repositions to a stowed vertical position at the side of the chair is Bauman et al., U.S. Pat. No. 5,683,136. The tablet must be pivoted from the horizontal to the vertical plane using one pivot joint then slid to a position along the side of the chair using a slide mechanism. This design does not allow repositioning of the tablet without rotating it from the horizontal plane, nor does it allow the tablet to be rotated within the horizontal plane.
Two designs that use angled pivot joints for positioning are Benoit, U.S. Pat. No. 4,216,994, and Phoon, U.S. Pat. No. 5,845,964. The angled pivot joints cause the tablet to be rotated through the horizontal and vertical planes simultaneously. Other designs, such as the patent to Sorenson, U.S. Pat. No. 5,765,911, allow motion in one plane independent of the other and movement of the tablet without upsetting its horizontal position. However, such designs require manual loosening and re-tightening of friction brakes before and after repositioning.
The alternative design of Kanigowski, U.S. Pat. No. 4,852,940, provides multiple axis motion using a single ball-joint, but fails to provide integral stops or locks. In order to maintain a horizontal position, the chair arms or a shelf extending from them must support the tablet. A design patent to Best, U.S. Pat. No. 409,860,illustrates a mountable accessory, requiring two mounting bars and two single-axis pivot joints to provide repositioning to a stowed position.
In light of the shortcomings of these prior devices, there remains a need for a tablet arm apparatus that allows the tablet to rotate to a vertical position or to move through the horizontal plane without upsetting the other plane of motion and without having to fully stow the tablet for a person to enter or exit of the seat of the chair while requiring only one mount and one inexpensive two-axis joint and furthermore, not requiring manual friction brakes to lock an axis of motion of the tablet.
Briefly describing one aspect of the invention, the work tablet arm apparatus includes a tablet plate for mounting a work tablet and an articulating arm assembly providing various tablet positions and configured for attachment of the apparatus to a chair.
The difficulties with prior chair tablet arm apparatuses are overcome in one aspect of the current invention by the articulating arm assembly. The arm assembly in one embodiment includes a pivot rod assembly connecting one end of a long arm to one end of a short arm. The other end of the long arm can be rotationally connected to the tablet plate using a slotted washer and stop pin combination that allows limited rotation of the tablet independent of the arm position. The other end of the short arm can be pivotably mounted to the chair arm, preferably as an integral element of the chair design. In one aspect of this embodiment, the short arm pivot provides a means for moving the tablet from a position over the seat of the chair to the front of or other side of the arm of the chair. This pivot allows a person to enter or exit the seat without having to fully stow the tablet and without upsetting the contents of the tablet.
In a further aspect, the pivot rod assembly provides a means for rotating the tablet and long arm about an axis parallel with the chair seat. The pivot rod assembly can include a bias spring for engaging a locking pin into a locking notch, stopping rotation of the long arm when the tablet is parallel to the chair seat. The long arm rotation about the pivot rod provides for quick movement of the tablet when it is not in use. When combined with a pivot to the outside of the arm of the chair, the long arm also provides for stowing the tablet in a vertical position along the outside of the arm of the chair. The chair tablet arm apparatus requires no manual friction brakes and no external support of the tablet other than a single mounting point.
In another embodiment of the invention a chair tablet arm apparatus is provided as an accessory to an existing chair design and is capable of two-axis motion using a single inexpensive hub and a single mounting bracket. The chair tablet arm apparatus in this embodiment can include a tablet plate, a pivot hub assembly, a mounting bar, and a mounting bracket. The mounting bracket can function to attach the apparatus to an existing member of the chair such as a chair leg. The mounting bar rotationally attaches the mounting sleeve to the pivot hub assembly. The pivot hub can be pivotably attached to the tablet plate.
The pivot hub assembly can include spring-biased pins that engage the mounting bar, and are operable to stop rotation of the hub around the mounting bar when the tablet is at a rotational position for pivoting. The tablet plate can then pivot between a position perpendicular to a position parallel to the chair seat. In the perpendicular position, the tablet can rotate independently within the perpendicular plane to a stowed position at the outside of the chair member to which the apparatus is attached.
One object of the invention is to provide a stowable tablet arm apparatus that can be readily integrated into an existing chair using a single mounting point. Another object is to such a tablet arm apparatus that can provide two-axis motion using a single inexpensive joint.
One benefit is that the tablet can be rotated to a vertical position or moved through the horizontal plane without upsetting the other plane of motion and without having to fully stow the tablet for a person to enter or exit the seat of the chair. Another benefit is that the apparatus requires no manual friction brakes to lock an axis of motion of the tablet.
These and other objects, advantages, and features are accomplished according to the devices, assemblies, and methods of the present invention.